check disk usage

check disk usage

[Xiaogeng (Shawn) Jin]

Hi,

My root filesystem is jffs2, which is mounted by kernel getting booting 
parameters "root=/dev/mtdblock3 rw" from the command line. I noticed 
that running 'df -k' only shows the usage of those devices that are 
mounted explicitly by 'mount' command but not the root filesystem. The 
following is the result of 'df -k' running on busybox-0.60.2.

# df -k
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/mtdblock0           16384       688     15696   4% /usr
/dev/mtdblock1           16384      5836     10548  36% /home
/dev/mtdblock2           16384       652     15732   4% /var

On a regular linux system, e.g. RedHat, we do get information about the 
usage of the root filesytem, right?

Is this a problem? If it's is, is it related to jffs2 or busybox?

Thanks,

Shawn.

Re: check disk usage

[Tino Keitel]

On Thu, Oct 17, 2002 at 13:58:46 -0700, Xiaogeng (Shawn) Jin wrote:
> Hi,
> 
> My root filesystem is jffs2, which is mounted by kernel getting booting 
> parameters "root=/dev/mtdblock3 rw" from the command line. I noticed 
> that running 'df -k' only shows the usage of those devices that are 
> mounted explicitly by 'mount' command but not the root filesystem. The 
> following is the result of 'df -k' running on busybox-0.60.2.
> 
> # df -k
> Filesystem           1k-blocks      Used Available Use% Mounted on
> /dev/mtdblock0           16384       688     15696   4% /usr
> /dev/mtdblock1           16384      5836     10548  36% /home
> /dev/mtdblock2           16384       652     15732   4% /var
> 
> On a regular linux system, e.g. RedHat, we do get information about the 
> usage of the root filesytem, right?
> 
> Is this a problem? If it's is, is it related to jffs2 or busybox?

Have you checked the strace output of df -k? As far as I can see, it
looks in /proc/mounts. Maybe this is of some help to you.

Regards,
Tino

-- 
tino.keitel@innominate.com
dipl.-inf.                        Innominate Security Technologies AG
software engineer                                   networking people
tel: +49.30.6392-3308                      http://www.innominate.com/

Re: check disk usage

[Henrik Nordström]

Haven't used busybox in a while, but when using "the real thing" the 
following applies, and it might apply to busybox mount as well:

This problem is caused by a /etc/mtab not beeing in synch with your actual 
mounts.

There is two ways to go about this

a) Propely set up /etc/mtab when booting. This is done by when having
/etc/mtab writeable, clear it, and then redo all mounts done up to that
point by using the -f option to only update /etc/mtab.

b) Do not use a real /etc/mtab. Link it to /proc/mounts. For details and
limitations of not using a mtab see the mount(1) man page.. almost all
setups can work just fine without a real mtab.

Regards
Henrik


> On Thu, Oct 17, 2002 at 13:58:46 -0700, Xiaogeng (Shawn) Jin wrote:
> > Hi,
> > 
> > My root filesystem is jffs2, which is mounted by kernel getting booting 
> > parameters "root=/dev/mtdblock3 rw" from the command line. I noticed 
> > that running 'df -k' only shows the usage of those devices that are 
> > mounted explicitly by 'mount' command but not the root filesystem. The 
> > following is the result of 'df -k' running on busybox-0.60.2.
> > 
> > # df -k
> > Filesystem           1k-blocks      Used Available Use% Mounted on
> > /dev/mtdblock0           16384       688     15696   4% /usr
> > /dev/mtdblock1           16384      5836     10548  36% /home
> > /dev/mtdblock2           16384       652     15732   4% /var
> > 
> > On a regular linux system, e.g. RedHat, we do get information about the 
> > usage of the root filesytem, right?
> > 
> > Is this a problem? If it's is, is it related to jffs2 or busybox?

Re: check disk usage

[Xiaogeng (Shawn) Jin]

> b) Do not use a real /etc/mtab. Link it to /proc/mounts. For details and
> limitations of not using a mtab see the mount(1) man page.. almost all
> setups can work just fine without a real mtab.
Thanks a lot. I did in this way to solve the problem.

Shawn.